Drill position indicator



' July 11, 1939. R. A. BOSSI DRILL POSITION INDICATOR Filed Feb. 8, 1939a I u F 0 nA M o 8 m Patented July 11, 1939 UNITED STATES PATENT OFFICE4 Claims.

This invention presents a drill position indi-- catorfor use incombinationwith portable drilling tools operated either by power ormanually. The object of the invention is to provide a sim- 5 ple andeflicient means by .which the workman may readily insure and maintainthe correct angular relation of the drill to the work under allconditions.

Such drilling tools. are employed in a wide variety of positions and inplaces of varying accessibility and it is often exceedingly difficultfor the workman to ascertain if the drilling tool is operating at therequired. angle, usually a right angle, to the surfaceof the work. If apositioning :base having a fixed relation to the drilling tool isemployed, it must be of limited area and is readily rocked with respectto the surface of the work so thatit cannot be depended upon to secureaccuracy of the required angular relationof the drilling tool'to thework.

The present invention has for its object to provide a simple andeflicient means by which a relatively small base isheld firmly seatedagainst the work irrespective of the angular relation of the drill tothe work while at the same time there is presented a means foraccurately indicating to the workman the required angular relation.

The object of the invention is further to provide such a device whichmay readily be attached to existing drilling tools.

These and other objects and features of the invention will appear morefully from the accompanying description and drawing and will beparticularly pointed out in the claims.

The device of the present invention may be used upon practically anytype of portable drill whether operated electrically, by compressed air,by other power means, or manually and is shown in the drawing ascombined with an electric drill of an ordinary type.

While the indicating device may be constructed as a part of the drill,it is preferably an independent device mounted upon or secured to thebody of the drill and thus may readily be attached to any existingdrilling tool.

The drawing discloses a simple and preferred embodiment of the inventionin which:

Fig. 1 is a side elevation, partially broken away, of an electricdrilling tool, together with a preferred embodiment of the presentinvention connected thereto.

Fig. 2 is a view in horizontal cross section taken on the line 2--2 ofFig. 1.

Fig. 3 is a small illustrative View illustrating the device shown inFig. I. adjusted for operation at an angle other than a right angle tothe work.

Fig. 4 is a detail in horizontal cross section showing one of the meansfor connecting the device to the drill body.

The electric drill shown is of an ordinary type presenting the body lwhich contains the motor and. a rigid operating handle grip 2 from whichthe conductor cable 3 leads. 'From the lower end of the body extends theusual rotating spindle 4 having the-chuck 5 in whichis mounted a twistdrill 6. The bodyof this type of drill is usually provided with acircumferential row of ventilating holes 1, two of which are hereconveniently used for attaching the device of the invention to thedrill.

The device as illustrated comprises a flat base 8, the lower face ofwhich may be provided with a friction surface to prevent slipping uponthe surface of the work 9 to be drilled. This base 8 is preferablybifurcated to allow the drill to work between the "bifurcations. 'At theend opposite the bifurcations there is rigidly connected to the base andextending upward therefrom a post It. Preferably the post is a firm rodscrewed into the base as illustrated and extending at right angles tothe base. At its upper end the post'is pro vided with an indicatorprojecting laterally from the post and having a point I I. Thisindicator is conveniently a screw l2 threaded through the post andprovided'with a .lock nut l3.

A leg is mounted on the drill body to permit rectilinear movement of thedrill body toward and from the Work. and means. are provided yieldinglyresistible to this movement of the drill body toward the work. This legpresents an outer surface one element of which constitutes a guidingelement and this guiding element is located parallel with the axis ofthe drill. The leg is also pivoted at its lower end by a universal jointto the base. While the leg as thus defined may vary in construction, itis preferably constructed as illustrated. That is, the leg comprises twotelescoping members, the upper of which is a hollow square tube l4 andthe lower of which is a square rod l5 telescoping within the uppermember and limited as to its telescoping movement by a screw l6 mountedon the member l4 extending into a slot I! in the member I5. The uppermember I l presents an outer fiat surface I8, the central longitudinalelement of which is the guide element, and the leg is so mounted on thedrill that this guide element extends parallel with the axis of thedrill. Any suitable means may be employed for mounting the leg upon thebody of the drill in the required relation. As shown, the upper end ofthe member [4 is filled with a block i 9 and a bolt 29 passes throughthis upper end and through the handle grip. Near the lower end of themember i l a clamp 2|. surrounds the member and is secured in place byscrews or bolts 22 passing through a pair of the holes '5 in the drillbody.

The yielding feature is here provided by an expansible spring 23 in thehollow member M between the upper end of the member and'the block l9.

At its lower end the leg is connected by a universal joint to the base.Such a joint is shown as formed by a foot 24 having bifurcations 25straddling the base and pivoted thereto at 26 and with the lower end ofthe leg member !5 passing through a slot 21 and pivoted to the foot at28 at right angles to the pivot 26. With this preferred construction,the point where the leg is actually pivotally connected to the base isoffset from the leg toward the axis of the drill so that pressure isapplied to the base fairly near the drilling point.

It will thus be seen with this construction there is provided ayieldingly compressible rectilinearly telescoping leg having its uppermember rigidly secured to the drill body and presenting an outersurface'having a guide element extending parallel with the drill axiswhile the lower end of the lower member is pivoted by a universal jointto the base.

The point II. of the indicator is positioned by the post I0 so as to bein a plane containing the axis of the drill and the guide element of thesurface l8. Hence when the indicator is adjustable, as is preferred, theadjustment must maintain the point in the said plane.

When the drill is pressed toward the work, compressing the spring 23,the base will be held firmly seated against the work irrespective of theangular relation of the drill axis to the work. But at all times theoperator of the drill is enabled to ascertain and maintain the requiredangular relation during the drilling operation simply by bringing theguide element of the outer surface of the leg into contact with thepoint of the indicator.

Usually the drill will be operated at right angles to the work asillustrated in Fig. 1 and the indicator l2 will be set for thatposition. When, however, it is desired to drill the hole at an angle tothe surface of the work, the indicator may be adjusted with respect tothe post to cause the guide element to be positioned at the requiredangle as shown in Fig. 3.

The device therefore enables the workman to drill with accuracy underall conditions and affords a very simple and eflicient means forsecuring that result.

Having thus described the invention, what is claimed as new, and desiredto be secured by Letters Patent, is

1. The combination with a drilling tool of a base adapted to seat firmlyagainst the work, a post rigidly connected to and extending upward fromthe base, a yieldingly compressible rectilinearly telescoping leg havingits upper member rigidly secured to the drill body and presenting anouter surface having a guide element parallel with the drill axis andhaving the lower end of its lower member pivoted by a universal joint tothe. base, and anindicator at the upper end of the post projectinglaterally therefrom with its point in a plane containing the axis of thedrill and the said guide element, in which when the drill is pressedtoward the work, yieldingly compressing the leg, the base will be heldseated irrespective of the angular relation of the drill axis to' thework and a required angular relation may be maintained during thedrilling operation by bringing the guide element and the indicator pointinto contact.

2. The combination as defined in claim 1, in which the indicator isadjustable with respect to the post to position its point toward andfrom the axis of the drill thus to adjust the angular relation of thedrill axis to the work.

3. The combination as defined in claim 1, in which the point ofconnection of the leg to the base is offset from the axis of the legtoward the axis of the drill.

4. The combination witha drilling tool of a base adapted to seat firmlyagainst the work, a post rigidly connected to and extending upward fromthe base, a leg mounted on the drill body to permit rectilinear movementof the drill body toward and from the work and presenting an outersurface having a guide element located parallel with the drill axis andhaving its lower end pivoted by a universal joint to the base, meansyieldingly resistible to movement of the drill body toward the work, andan indicator at the upper end of the post projecting laterally therefromwith its point in a plane containing the axis of the drill and the saidguide element, in which when the drill is pressed toward the work thebase will be held seated irrespective of the angular relation of thedrill axis to the work and a required angular relation may be maintainedduring the drilling operation by bringing the guide element and theindicator point into contact.

ROMEO A. 30831.

